Xfinity [Edited] my phone

I traded in my iPhone 12 Pro in September with the $700 new account promotion. My account was never credited. I have the tracking number that proves Xfinity received my phone. I have chatted 3 times and called 3 times to get this resolved and have been "assured" it will be handled. It has not been addressed. I called today to get it resolved again spent 45 mins on the phone and was eventually transferred to a supervisor. The supervisor picked up the line and then hung up on me.